Eugène is first introduced in La fortune des Rougon as a key player in the coup d'état of 1851 which established Napoleon III as Emperor of the French.
Eugène's maneuverings establish his parents' control over the town of Plassans and lay the foundations for solidifying the family fortune.
In conflict with the Emperor over an inheritance claim involving a relative of the Empress, Rougon resigns from his position as premier of the Corps législatif before he can be dismissed.
This puts the plans and dreams of Rougon's friends in limbo, as they are counting on his political influence to win various personal favors.
Instead, he encourages her to marry M. Delestang, a man of great wealth who can easily be wheedled, while he himself takes a respectable nonentity of a wife who will not hinder his ambition.
In consequence, after the attempt is made (the Orsini incident of 1858), the Emperor makes him Minister of the Interior with power to maintain peace and national security at any cost.
Ostensibly, the appointment is meant to reconfigure the country on less imperialistic, more liberal lines, but in reality Rougon has a free hand to crush resistance, curtail opposition, and control the press.
in his opinion: "with all due allowance for its somewhat limited range of subject, Son Excellence Eugene Rougon is the one existing French novel which gives the reader a fair general idea of what occurred in political spheres at an important period of the Empire.
He is the incarnation of that craving, that lust for power which impelled so many men of ability to throw all principle to the winds and become the instruments of an abominable system of government.
All of the descendants of Adelaïde Fouque (Tante Dide), Eugène's grandmother, demonstrate what today would be called obsessive-compulsive behaviors to varying degrees.
Zola also strongly suggests that the corrupt environment of Second Empire politics and society is what allows Eugène's personality and desire for power to be nurtured and fulfilled.
In Le docteur Pascal (set in 1872), Zola tells us that Eugène becomes a deputy in the legislative assembly and remains a staunch defender of the Emperor and the Empire after the Franco-Prussian War.